Maybe the light version has all of the graphics and sound as the original, but they just block your access to that data with extra code. Or they have a bunch of extra advertising to the buy the full version...
Agreed. Most of the code is going to involve the SIGNIFICANT AI needed to run the game. Even in lite mode you need the AI. There also are screens advertising the full that obviously aren't on the full.
This is exactly what they do. They comment it out. Lite versions have the exact same size as full versions.